Comprehensive Study of the Chloro Porphyrin Fe(III) Complex: Synthesis, Spectroscopic Analysis, Structural Characterization, Electronic Properties, and DFT Calculations

ABSTRACT Iron(III) penta‐coordinated porphyrin complex [FeIII(TTP)Cl] (TTP = meso ‐tetra( para ‐methylphenyl) porphyrinate) has been studied by single‐crystal x‐ray diffraction, 1 H NMR spectroscopy, density functional theory (DFT) calculation of its electronic structures, and Hirshfeld surface (HS) analysis. The average equatorial iron–pyrrole nitrogen bond length (Fe–Np = 2.063(9) Å) and the distance from the iron to the 24‐atom mean plane of the porphyrin ring (Fe–P C = 0.496 Å) are consistent with those observed in other five‐coordinated Fe(III) high‐spin complexes. The 1 H NMR spectroscopy combined with x‐ray crystallographic analysis shows that the Fe(III) center has a high spin ( S = 5/2). The chlorido iron(III) meso ‐arylporphyrin complex was studied by exploring the DFT at the level of B3LYP‐D3/LanL2DZ. The optimized chemical structure aligns well with experimental data. A small highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) gap indicates high reactivity and electron‐donating ability. All theoretical calculations were carried out to investigate the structural and electronic properties of the [Fe III (TTP)Cl] complex. Molecular electrostatic potential (MEP) highlights strong Fe–N electrophilic interactions and the presence of several complex electrostatic interactions between groups, which may contribute to the enhanced stability of the compound within the crystal lattice. HS analysis reveals key intermolecular interactions stabilizing the crystal lattice.